new ssb phase noise, concepts and applications · 2020. 10. 11. · 1 rohde & schwarz10/14/2020...

Rohde & Schwarz1 10/14/2020

SSB PHASE NOISE, CONCEPTS AND APPLICATIONS

Chen Peng / Frank-Werner.ThuemmlerOctober 14, 2020

RF and Microwave Design

SSB Phase Noise, Concepts and Applications

SSB PHASE NOISE, CONCEPTS AND APPLICATIONS

Rohde & Schwarz

AGENDAl Phase noise basics

l Time and frequency representationl Applications where low phase noise is neededl Phase noise categoriesl Phase noise for pulsed signalsl Phase noise vs. jitter

l Frequency synthesis and its impact on phase noisel Phase noise enhancement options of the and their influence on the

l RF output signall Clock synthesizer signal

l External reference and reference couplingl Influence on phase stabilityl Bandwidth and Locking Range

3 SSB Phase Noise, Concepts and Applications10/13/2020

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Frequency domain Time domain

w/o phase noise w/o jitter

CW SIGNAL BY IDEAL SIGNAL SOURCETIME DOMAIN VS. FREQUENCY DOMAINAn ideal analog signal source delivers a pure sinusoidal signal with a stable frequency and without any noise.


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CW SIGNAL BY REAL SIGNAL SOURCETIME DOMAIN VS. FREQUENCY DOMAIN► The frequency representation of a real signal

source has some non-ideal properties:

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with phase noise with jitter

§ Harmonics§ Non-harmonics§ The amplitude fluctuates (amplitude noise)§ The frequency varies§ slowly due to aging, temperature drift§ rapidly due to phase noise

SSB Phase Noise, Concepts and Applications10/13/2020

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WHY IS LOW PHASE NOISE DESIRABLE?APPLICATION EXAMPLES

Radar applications Base station receiver testing► Phase noise masks slow moving targets ► Phase noise yields interference

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- 37

Hz

CW or modulated signal

CW only


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WHY IS LOW PHASE NOISE DESIRABLE?APPLICATION EXAMPLES Generating modulated signals► Phase noise affects EVM performance

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LO

Increasing phase noise of the LO signal


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WHY IS LOW PHASE NOISE DESIRABLE?

ADC testing► Phase noise (-> jitter) causes incorrect

sampling► Sampled amplitudes deviate from expected

amplitudes

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ADCClock input Analog input


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PHASE NOISE CATEGORIES

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Wideband noise =Wideband phase noise + Wideband amplitude noise

Assumption for large offsets (e.g. > 10 MHz):Phase noise and amplitude noise power densities equal

Close-in phase noise

Wideband phase noise

Pedestal phase noise


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PHASE NOISE FOR PULSED SIGNALS

► Spectrum of pulse train is periodic with pulse repetition frequency (PRF)

► Phase noise contributions of different spectral lines overlap

► Thus phase noise of a pulsed signal is higher than that of a CW signal

► Actual difference depends on pulse parameters (width, PRI, …)

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PulsedCW

0.5/PRI = 5kHz1/PRI = PRF = 10kHz


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RELATION BETWEEN PHASE NOISE AND JITTER

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► Jitter can be determined from phase noise


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ALC modulator

detector

electronic attenuator

synthesizer

output amplifier

ALC loop

ALC ‚on‘

ALC ‚off‘

control voltage for level setting

AM control voltage

…pulsemod

filter

Synthesizer unit Output unit Step attenuator

ANALOG SIGNAL GENERATORSIMPLIFIED BLOCK DIAGRAM


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ANALOG SIGNAL GENERATORSIMPLIFIED BLOCK DIAGRAM

ALC modulator

detector

electronic attenuator

synthesizer

output amplifier

ALC loop

ALC ‚on‘

ALC ‚off‘

control voltage for level setting

AM control voltage

…pulsemod

filter

Synthesizer unit Output unit Step attenuator


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FREQUENCY SYNTHESISBASIC CONCEPT

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VCOLPReference

Source

Phase-Locked Loop (PLL)DividerN

PhaseComparator


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INFLUENCE OF VCO

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VCO


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INFLUENCE OF REFERENCE SOURCE

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Reference Source


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REFERENCE SOURCE AND VCO

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VCOReference Source


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Reference Oscillator

Phase Noise of analogSignal Source (Generator)

REFERENCE SOURCE AND VCO

VCO


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Loop Bandwidths: 100 kHz

Phase Noise of analog

Signal Source (Generator)

What happens if we changethe loop bandwidth?


INFLUENCE OF LOOP BANDWIDTH

VCO


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VCO


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Different Loop Bandwidths: 20 kHz 100 kHz 400 kHz



VCO


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MAIN PHASE NOISE CONTRIBUTIONS


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CrystalOscillator

Multiplier(with PLLs)

Reference Source

Main PLLVCO

Main Synthesis

VCOLPReference

Source


PhaseComparator

MAPPING OF CIRCUIT CONCEPT TO RF PATH

RF out

Synthesis determines phase noise above a specific carrier offset.

Reference determines phase noise below a specific carrier offset.

Simplified block diagram

Circuit concept


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CrystalOscillator


Reference Source

Main PLLVCO

Clock Synthesis

VCOLPReference

Source


PhaseComparator

MAPPING OF CIRCUIT CONCEPT TO CLK SYN PATH

Clk Syn out

Synthesis determines phase noise above a specific carrier offset.

Reference determines phase noise below a specific carrier offset.

Simplified block diagram

Circuit concept


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CLK SYN AND RF PATH SHARE THE SAME REFERENCE SOURCE

Main PLLVCO

Clock Synthesis

CrystalOscillator


Reference Source

Main PLLVCO

Main Synthesis

RF out

1 GHz

Clk Syn out

ALC & step attenuator


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STANDARD


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HIGH PERFORMANCE OCXO REFERENCE OSCILLATOR


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IMPROVED CLOSE-IN PHASE NOISE PERFORMANCE


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ULTRA LOW PHASE NOISE


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WHAT IS A YIG OSCILLATOR?

Oscillator with a resonator made from yttrium iron garnet (YIG)

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300 µm


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YIG OSCILLATOR: PROS AND CONS

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► Pros- Low phase noise- Low wideband noise

► Cons- Price- Settling time


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Different Loop Bandwidths: 20 kHz 100 kHz 400 kHz

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VCO


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INFLUENCE OF MAIN PLL BANDWIDTH

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PLL BW „normal“

PLL BW „narrow“


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REFERENCE COUPLING

► The SMA100B offers a number of reference inputs and reference outputs- Standard: 10 MHz Reference input and output- K703: 100 MHz, 1 GHz Reference input and output- K704: Flexible Reference Input (1 MHz to 100 MHz)

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1 GHzCrystalOscillator


Reference Source

Main PLLVCO

Main Synthesis

SMA100B

RF out

1 .. 100 MHz


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NO REFERENCE COUPLING

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CrystalOscillator


Reference Source

Main PLLVCO

Main SynthesisSMA100B

RF out

CrystalOscillator


Reference Source

Main PLLVCO


RF out

Phase Drift:Arbitrary


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1 .. 100 MHZ REFERENCE COUPLING

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CrystalOscillator


Reference Source

Main PLLVCO


RF out

1 ..

100

MH

z

CrystalOscillator


Reference Source

Main PLLVCO


RF out

Phase Drift:Better


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1 GHZ REFERENCE COUPLING

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CrystalOscillator


Reference Source

Main PLLVCO


RF out

CrystalOscillator


Reference Source

Main PLLVCO


RF out

Phase Drift:Best1

GH

z


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REFERENCE COUPLING: OVERVIEW

Ref Coupling Phase Driftnone Arbitrary10 MHz Better than nothing100 MHz Better1 GHz Best

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Ref

RF out 1

RF out 2


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REFERENCE COUPLING: BANDWIDTH AND LOCKING RANGE

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VCOBWExternal

Reference

Phase-Locked Loop (PLL)

PhaseComparator

Lock

ing

Ran

ge

“1 GHz + 3 ppm“

“1 GHz - 3 ppm“


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REFERENCE COUPLING: BANDWIDTH AND LOCKING RANGEExt. Ref Freq Sync. Bandwidth Minimum locking range10 MHz Narrow 0.5 Hz +/- 0.15 ppm +/-1.5 Hz10 MHz Wide 100 Hz +/- 3 ppm +/- 30 Hz100 MHz Narrow 0.5 Hz +/- 0.15 ppm +/- 15 Hz100 MHz Wide 250 Hz +/- 3 ppm +/- 300 Hz1 GHz Narrow 5 Hz +/- 3 ppm +/- 3 kHz1 GHz Wide > 50 kHz +/- 3 ppm +/- 3 kHzVariable (1 .. 100 MHz) Narrow 0.5 Hz +/- 0.15 ppmVariable (1 .. 100 MHz) Wide 5 Hz +/- 3 ppm

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High flexibility to couple SMA100B to reference sourcesof different qualities and characteristics.


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THANK YOU

10/13/202010/13/2020 SSB Phase Noise, Concepts and Applications

new ssb phase noise, concepts and applications · 2020. 10. 11. · 1 rohde & schwarz10/14/2020...

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